1. Field of the Invention
The present invention relates generally to tissue treatment systems and in particular to a reduced pressure treatment system having a system for distinguishing between a leak condition and a disengaged canister condition.
2. Description of Related Art
Clinical studies and practice have shown that providing a reduced pressure in proximity to a tissue site augments and accelerates the growth of new tissue at the tissue site. The applications of this phenomenon are numerous, but application of reduced pressure has been particularly successful in treating wounds. This treatment (frequently referred to in the medical community as “negative pressure wound therapy,” “reduced pressure therapy,” or “vacuum therapy”) provides a number of benefits, including faster healing and increased formulation of granulation tissue. Typically, reduced pressure is applied to tissue through a porous pad or other manifolding device. The porous pad contains cells or pores that are capable of distributing reduced pressure to the tissue and channeling fluids that are drawn from the tissue. The porous pad often is incorporated into a dressing having other components that facilitate treatment.
One problem with current reduced pressure systems is the interruption of reduced pressure to the tissue site when a leak develops in the system or a component of the system, such as a fluid collection canister, becomes disengaged. Previous reduced pressure systems used a flow sensor to determine the amount of air flow moving through the reduced pressure system. Upon detecting a “high” flow rate, an alarm condition indicating “Canister Not Engaged” was typically activated. If a slightly lower flow rate was detected, it was assumed that a leak had developed, and an alarm condition indicating such was activated. Using a flow sensor to detect these conditions has certain drawbacks. The addition of flow sensors to the reduced pressure system requires additional hardware and the associated software required to receive and process data from the flow sensors. The flow sensors also may exhibit decreased accuracy due to certain environmental conditions. For example, when the flow rate sensor determines flow by measuring a pressure drop across an orifice, temperature conditions may dramatically affect the hardware sensing the pressure drop, thereby presenting errors in the final flow rate determination.